Centrifugal mineral separator



Patented Nov. 1, I932 PATENT OFFICE LAURITS I. LORENTSEN, F VANCOUVER, BRITISH COLUMBIA, CANADA CENTRIFUGAL MINERAL SEPARATOR v Application filed December 15, 1930, Serial No. 502,273, and in Canada November 25, 1930.

My invention relates to improvements in centrifugal mineral separators which are particularly adapted for use in dealing with black sands containing'flour gold and platinum. V

The object of the invention'is to provide means whereby a continuous disturbance of pulp passing through the machine ismaintained in order that the minute particles of precious metals are brought into direct contact with a body of mercury. A further object is to difi'erentiatc between the centrifugal velocity of the mercury and the pulp, whereby the mercury movement is mainis tained at one velocity and the pulp at a higher velocity, with the latter so agitated by auxiliary water as to keep the sand in suspension therein until discharged from the -machine. The invention consists essentially of a T0- tating bowl adapted to support a body of mercury by centrifugal force upon its side Walls, an impeller pump for directing the pulp upwards across the mercury means for supplyinga water flow to the pulp in its passage across the mercury, and means for causing mechanical disturbance to the pulp,

as will'be more fully described in the following specification and shown in the accompanying drawing.

Fig. 1 is asectional view of the invention.

Fig. 2 is a plan view taken on the line 22 of Figure 1.

Fig. 3 is an enlarged fractional plan view showing the pulp disturbance due to the auxiliary water flow and mechanical agitationg v Fig. 4 is a fractional plan view showing a modified form of scraper. 40 Fig; 5 is an elevational View of same.

Inthe drawing like characters of reference indicate corresponding parts in each figure. v v

The numeral 1 indicates generally a base having a concentrically arranged step bear ing 2 and supporting a frame 3 in which an upper bearing 4 is incorporated.

Surrounding the base 1 is a casing 5 having outer and inner side walls 6 and 7 respectively connected together by a sloping bottom wall 8 to define a launder 9 having a tailings discharge opening 10 and a mercury recovery plug 11, which latter is situated at the lowest part of the bottom wall 8. -The casing 5 is surmounted with an annular rim 12 having radial members 13 which support an elongated vertical bearing 14 which is mounted in alignment with the bearings 4 and 2. Mounted in the bearings 4 and 2 is a vertical shaft 15 which supports a heavy bowl 16 having a cup shaped bottom wall 17 and outwardly inclined side walls 18 provided with an annular recess 19 which is adapted when the bowl is being rotated at a suitable speed to support a column of mercury of a depth equal to that of the recess. The shaft 15 is fitted with a bevel gear 20 which is driven from a bevel pinion 21 mounted upon a shaft 22, which shaft is suitably journalled and is fitted with a driving pulley 23 and a driven pulley 24. I

Suitably journalled above the rim 12 and one of the radial members 13 is a horizontal shaft 25' having a bevel pinion 26 at its inner end and a pulley 27 at its outer end, which latter is driven by a belt 28 from the driven pulley 24. The pulley 27 is smaller in diameter than the pulley 24, so that the shaft 25 is driven at a greater speed than the shaft 22. Rotatably mounted in the vertical bearing 14 is a tubular shaft 29 which is bell mouthed at its upper end as at 30, the shaft forming a feed pipe and the bell mouthed portion 30 forming a feed hopper 31 thereto.- Fitted to the shaft 29 is a bevel gear 32 which meshes with the pinion 26 and is driven thereby.

Mounted upon the lower end of the shaft 29 and formed integrally therewith is a dis- 7 'tributor 33 consisting of a pair of substan-' tially cup shaped members 34 which are "i velocity spaced apart an appreciable distance adjacent their centres and are upturned and close- 1y arranged at their peripheries. A plurality of impeller blades connect the cupped members 34 together, which extend to their periphery and divide the interspace between them at that point into a plurality of impeller orifices 36, so that when the distributor 33 is rotated at a suitable speed the material delivered to the hopper 31-will be dis- 15 'v in "0' l S' and connects with an annular pi e 40 which in turn connects with a plurality of substantially vertical branches or spray pipes 41 having outlet orifices 42 so arranged as to direct a water flow in the direction of peripherai travel of the bowl 16. Extending radially outward from the tubular shaft 29 is a plurality of arms 43 each supporting a scraper 44 havin a relatively sharp leading 2& nd a, re atively broad trailing edge i i" I supported above the bowl 16 is an aiimflar eflector plate 47 which is downwardly turned at its outer edge as at 48 to deflect the fl'ow of material downwardly into the launder 9 as it is discharged from the Bathe modification shown in Figures 4 and 5Qthe scrapers 44 are pivotally con- 'nected to the arms 43 by links 49 and are fittedwith a plurality of short chains or other flexible members 50, which scrapers aild chains are adapted to be urged into contactwith the mercury wall by centrifugal fiance to keep the sand contacting therewith, in; a continuous state of agitation, thus preventing it from forming a layer or coating on the mercury which would impede the p of values therethrough.

' Hav" thus described the several parts of I will now briefly explain its wea sadpwnwardlythrou h the tubular shaft 29,

between the imp ler blades 35 and the cupped member 34 of the distributor 33 which impart a rotary and a centrifugal motion thereto, discharging it at a relatively high in a rotational and upward direction across. the inner periphery of the merwau. The impeller orifices 36 of the 'hutor are less in cross sectional area than the inner portions of the passages fonned by'the impeller blades and the tubular shaft 29, so that when an appropriate feed is maintained the tubular shaft is full of pulp, thus producing a head pressure to accelerate the upward flow of pulp from said orifices. As the side walls of the bowl and coincidentally the inner peripheral surface of the mercury wall, are outwardly inclined, the pulp tends to flow upwards in a substantially even stream to discharge. With but a single bowl, if sufiicient peripheral velocity only is maintained to support the column of mercury, the sand and values will precipitale i'l m tlia water and will be carri d round upon the surface of the mercury, but by provldin the spray pipes 41, which are rotated at a her speed than thebosrb and discharge water in the direction of travel, the sand is being continually disturbed and kept substantially in a state of suspension in the water, thus permitting the heavier material or values to become separated and precipitated onto the mercury wherein it, is amalgamated, or otherwise received.

Obviously the water from the spray pi as quickly loses its velocity after reachlng mercury wall but is a am a itated b the 1:0- tating scrapers 44 which de ect its ow tern.- porarily inwards, thus causing eddies behind the trailing edges 46 and maintaining the lighter mineral such as the sand, in suspension in the water until it is carried over the to of the bowl and, into the launder 9.,

hile spray pipes may be stationar with their jets arranged in the direction of rota.- tion of the bowl, I prefer to use the rotating spray pi shown, as by so doing a rela tively Iig t water pressure only is required to cause a discharge from the pipes at a, considerably higher velocit than the peripheral travel of the bowl. f the material discharged from the bowl, any mercury will accumulate below the discharge opening 10 and may be withdrawn at suitable intervals by removing the plug 11 and the tailings will flow outwards from the opening 10.

What I claim as my invention is:

1. In a centrifugal mineral separator havin a rotatable bowl adapted to support a co umn ofmercu by centrifugal force, and

means for delivering pul to the base of the bowlfor passage upwar across the inner surface of the mercury column, a scraper rotatablewithin the bowl adapted to agitate the pulp while in contact with the mercury column, said scraper bein flexibly connected tovarms mounted for rotation within the bowl whereby the scraper is urged into contact with the mercury column by centrifugal force, and a plurality of flexible members attached to the scraper adapted to increase the zone of agitation of. the pulp. I

2. A centrifu al mineralseparator having a rotatable bowl adapted to support a. substantially cylindrical column of mercury by centrifugal force, a tubular rotatable shaft concentric with the bowl, an impeller secured to the base of the shaft adapted to discharge pulp fed into the shaft from the base of the mercury column upwards thereacross, means for rotating the bowl and the shaft at different speeds, a spray pipe rotatable with the shaft adapted for connection to a source of Water supply, and arranged to deliver water to the inner surface of the mercury column in the direction of rotation of the bowl.

Dated at Vancouver, B. (1, this 9th day of December, 1980.

LAURITS I. LORENTSEN. 

